Decking system and anchoring device

ABSTRACT

The present invention is an anchoring device for joining three boards. It includes a substantially flat horizontal top element having a top view configuration which includes two sides and has a first predetermined width as measured wide to side at its maximum width between the two sides. There is at least one substantially vertical support member attached to the underside of the top element along an imaginary center line and extending downwardly from the top element for a predetermined length, which has two sides and a second predetermined width as measured at its maximum width. There is a substantially flat horizontal bottom element with two sides and has a third predetermined width at its maximum width. The first predetermined width is greater than the second predetermined width and the third predetermined width, and the third than the second. The invention also includes a decking system utilizing the anchoring device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to an improved anchoring device for joining adjacent boards, e.g. decking systems, more specifically, the invention is an anchoring device, as well as a system containing an anchoring device and decking boards in combination. The system provides the ability for pre-setting distances between adjacent boards and attaching to at least one joist board while securing at least one adjacent board. Thus, the anchoring device physically joins two adjacent boards in the same plane to a third, supporting board.

2. Information Disclosure Statement

The following patents are representative of the state of the art for wood joining devices, equipment and methods:

U.S. Pat. No. 1,184,080 to D'Arcy describes a structure of the class described, the combination of frame pieces disposed at an angle to each other and plate-like corner irons having angularly disposed flanges, said corner irons being arranged in opposed pairs on the sides of and secured to the ends of meeting frame pieces with their flanges engaging the inner edges thereof in overlapping telescoping relation to each other, the inner flanges having vertical nail slots therein and brads on their edges driven into the frame pieces, the outer flanges having nail perforations opposite the nail slots, there being nails disposed through the said perforations and slots and driven into the frame.

U.S. Pat. No. 2,332,081 to G. M. Hunt et al is directed to a wooden panel. It is described as a panel comprising wooden strips joined along their edges with glue, each strip having at least one groove in its edge matching groove in the edge of the adjoining strip, an asbestos millboard spline fitted in the matching grooves and bridging the joint between the strips, crossbands covering the strips on both sides of the panel, and veneers covering the crossbands.

U.S. Pat. No. 2,362,252 to Ellinwood describes a wall structure of the character described comprising a pair of adjacent wallboard panels having meeting edges, each of said panels being formed with a groove opening into its meeting edge, the groove in each panel providing an outer lip and an inner lip, said outer lips being in abutting relation, a joining strip permanently secured to the under surface of said outer lips, said inner lips being spaced, a T-shaped connecting member movably positioned in said groove and having a base in spaced relation to said inner lips, and means for anchoring said connecting member to a structural element.

U.S. Pat. No. 2,398,603 to Soderberg describes a joining staple, comprising a metal body having at least two portions extending at right angles to each other and at least two teeth carried upon each of said portions, each of said teeth consisting of a flat substantially rectangular body having a cutting edge extending substantially parallel to its body portion, the cutting edges of all of said teeth being located in one plane, each of said portions having another cutting edge extending between the teeth of that portion, the second mentioned cutting edges being also located in one plane.

U.S. Pat. No. 2,406,387 to Lank describes the method of constructing a plurality of wooden posts each of which has a connector element incorporated therein adjacent each end thereof which method comprises forming a plurality of longitudinally extending grooves in one side of each of a pair of wooden blanks from which the posts are to be formed, forming a transverse groove adjacent each end of said side of each of said blanks with the transverse grooves intersecting the longitudinal grooves, providing a pair of connector retaining members with a plurality of seats for receiving connector elements, the number and spacing of said seats in each of said connector retaining members conforming to the number and spacing of the longitudinal grooves in each of said blanks, placing connector elements in each of said seats, positioning said blanks with their grooved sides together and with said connector retaining members in said transverse grooves, bonding said blanks together, and severing the thus bonded assembly along longitudinal lines intermediate said longitudinal grooves.

U.S. Pat. No. 4,641,988 to Ganner is directed to a fitting for releasably joining two structural components. It is illustrated for releasably joining two structural components particularly plate-shaped structural components which extend at a right angle relative to one another, a fitting has a preferably cylindrical locking element which can be inserted either directly in a bore in the first structural component or it can be inserted indirectly in a housing, and a holding piece with a holding projection anchored in the second structural component. In the assembled position, the holding projection & abuts against one or two gripping surfaces of the locking element which gripping surfaces are of, for example, eccentric shape, and the holding projection is pulled toward the locking element when the locking element is turned. The holding piece is constructed plate-shaped and is insertable in a slot in the second structural component.

U.S. Pat. No. 4,682,458 to Sparrow describes a floor composed of parallel spaced beams having flanges and blocks of polystyrene foam which are laid on the flanges to bridge the gaps between the beams. Boards are laid on the polystyrene blocks, and are supported by the blocks, which form load-bearing members of the floor. The blocks may have flanged portions extending over the beams, so as to provide heat insulation.

U.S. Pat. No. 5,004,027 to Legler et al illustrates a biscuit joiner. It is described as a biscuit joiner for cutting semi-elliptical slots in opposing edges of workpieces which are to be joined along those edges includes a housing adapted to be mounted upon the quill of a multi-purpose woodworking tool, which housing encloses a rotary saw blade adapted to be attached to a spindle projecting from the quill on which the housing is mounted. A spring loaded guide projects from the front face of the housing and has a slot therethrough, so that when the front face of the guide is engaged by an edge of a workpiece to be slotted the guide can be pushed inwardly against spring pressure, allowing the rotary saw blade to be exposed and form a slot in the edge of the workpiece. Adjustable stops are provided on the guide so that a desired depth of cut will automatically be made after adjustment. An alternative construction of this biscuit joiner is especially adapted for use in conjunction with a conventional drill press, with the arbor which carries the saw blade being clamped in the chuck on the drive spindle of the drill motor.

U.S. Pat. No. 5,071,280 of Turner describes a sheet metal connector that is provided for use with timber building components of the type that has nails to be driven through the sheet metal into the timber. The connector has substantially U-shaped cuts in the sheet metal to define nailing tongues. The nailing tongues have a deformation for use in providing a nail entry point so that a nail driven therethrough will serve to drive the nailing tongue into the timber.

U.S. Pat. No. 5,160,211 to Gilb describes a connector for securing a wood railing to a wood post by fasteners which are in shear in relation to all forces imposed upon the railing. The connector is a single piece sheet metal member formed in a generally triangular cross section with openings provided for the insertion of the fasteners. The connector is placed on the underside of the railing to eliminate all top nailing or driving of screws through the top side of the rail.

U.S. Pat. No. 5,182,891 to Slocum describes a flooring construction which is provided having a unitary construction with a top layer providing a finished flooring surface and an insulation layer adjacent the top layer. The flooring panel includes an upper portion and a lower portion. The upper portion has a larger dimension than the lower portion and extends outwardly beyond the lower portion. A recessed portion between the upper portion and the lower portion defines a channel. A plurality of interlock support elements having a vertical web and an upper horizontal flange are arranged so that the horizontal flange extends into the channel. The vertical web extends below the lower portion to raise the flooring.

U.S. Pat. No. 5,251,996 to Hiller et al describes a connecting element for connecting two parts generally in a connection plane has a first portion for connecting the element relative to a first of the parts and second portion for connecting the element relative to the second part. The second portion includes actuation members which on relative movement of the parts substantially along the connection plane urge the parts forcefully towards each other.

U.S. Pat. No. 5,377,732 to Fujii et al illustrates a wood joining structure and method thereof. It is described as a technique is provided for joining wood members. A plurality of slits are formed on the end portions of wood pieces desired to be joined, and the end portions are abutted with corresponding slits in alignment to form a common surface. Each of the abutted wood end portions is fixed by temporary fixing means to a desired joining state. Thereafter, an adhesive agent is applied into the interior surfaces of the slits. Connecting plates, e.g., made of a reinforced plastic material coated with the adhesive agent, are inserted into the aligned slits. The adhesive agent is then hardened.

U.S. Pat. No. 5,419,649 to Gilb describes an intermediate rail to post connection including a sheet metal connector for attaching a wood intermediate rail to a wood post is disclosed. The sheet metal connector is preferably formed with a base member, an integral seat member and a post engaging flange. Preferably four fasteners which may be either screws or nails are inserted through suitable openings in the sheet metal connector. Two of the fasteners pierce the sheet metal connector, the intermediate rail and the post in such a way as to be in double shear. The other two fasteners are inserted through the sheet metal connector directly into the wood post. The sheet metal connector is placed on the underside of the intermediate rail and all fasteners are therefore inserted from the underside of the intermediate rail.

U.S. Pat. No. 5,458,433 to Stastny explicates a biscuit and joint made using same. It is described as a biscuit having octagonal outer periphery is used to form a joint between first and second workpieces. The biscuit fits within arcuate slots formed in the workpieces, with glue placed in the slots and/or on the biscuit before the joint is put together. The biscuit is made of an anhydrous compressed wood.

U.S. Pat. No. 5,480,117 to Fleming, III describes a bracket for mounting a rotary lock member in the frame of a panel which is provided. The bracket is a preferably U-shaped body having a base and two legs extending therefrom. The inner dimension of the bracket is chosen to allow insertion of a rotary lock member therein. Panel engaging steps and protrusions are located on the outside surface of each leg for engaging the frame material. The legs of the bracket are biased inwardly towards one another, such that when a locking member is inserted therein, the legs are pressed outwardly, driving the protrusions into the frame material. A number of bores are located in the bracket to allow supplemental locking members to lock the bracket to the frame.

U.S. Pat. No. 5,529,428 to Bischof is directed to a metallic structural element for connecting workpieces consisting of wood, woodworking material or plastic. It is described as a metallic structural element for connecting workpieces consisting of wood, woodworking material or plastic, consisting of a lamellar part, which provides the non-positive connection with the first workpiece provided with a groove and a transverse hole, and a bolt-like part which, through screwing or pinning, realizes the non-positive connection with the second workpiece provided with a longitudinal hole. The lamellar part has, in the center, a hole which is at right angles to the plane of the lamella and is intended for fixing in the groove of the workpiece. Variants having a wing-like long or rectangular short lamellar part and a bolt-like part in the form of a conical wood screw, cylindrical screw, screw having a metal thread, threaded sleeve or pin. Accessories: screwing tool and drilling template.

U.S. Pat. No. 5,564,248 to Callies describes a construction hanger for supporting a joist, rafter or the like to a support beam, in which the hanger is provided with a holddown tab for insuring proper seating of the joist to hanger during the installation process. The invention also relates to a method of making such a hanger.

U.S. Pat. No. 5,603,580 to Leek et al describes a positive fastener-angling device for positioning an elongated fastener with respect to the face of a sheet metal connector and a wood member only at a preselected angle which is substantially less than 90 degrees by forming a slit-cut in the sheet metal connector by means of a die which progressively at the same station, forms a fastener guideway in the shape of a half cone. The fastener opening and the guideway are dimensioned so that the fastener can only penetrate the sheet metal connector at a preselected angle set at the factory.

U.S. Pat. No. 5,660,016 to Erwin et al describes an extruded plastic decking plank for mounting to an underlying support structure, the plank having a rigid foam core, a resilient outer plastic shell, and a clamping portion for securing the plank to the support structure. The top surface of the plank can be provided with a non-slip surface. The invention also includes an attachment system for securing such decking planks to a support structure by engaging the clamping portions of the decking planks onto clamps or hold down blocks which are secured onto the support structure, and which permit relative motion between the planks and the structure in the planks' lengthwise direction to prevent stress and buckling caused by uneven expansion.

Notwithstanding the prior art, the present invention is neither taught nor rendered obvious thereby.

SUMMARY OF THE INVENTION

The present invention is an anchoring device for joining three boards. It includes a substantially flat horizontal top element having a top view configuration which includes two sides and has a first predetermined width as measured side to side (This first predetermined width is measured at a maximum width between the two sides). The top element has an imaginary center line and there is at least one substantially vertical support member attached to the underside of the top element along the imaginary center line and extending downwardly therefrom for a predetermined length. This substantially vertical support member has two sides and a second predetermined width as measured side to side at its maximum width. There is also a substantially flat horizontal bottom element having a flat bottom view configuration which includes two sides and has a third predetermined width as measured side to side at its maximum width.

The first predetermined width is greater than both the second predetermined width and the third predetermined width, and the third predetermined width is greater than the second predetermined width. By this configuration, the present invention anchor device is adapted to maintain the top element in a predetermined position during use for joinder of two adjacent boards which have been pre-cut with receiving slots, and to position the bottom element upon a support board on which the two adjacent boards rest for attachment of the anchoring device to the support board for anchoring and support of the two adjacent boards.

Preferably, the anchoring device bottom element has a generally trapezoidal shape with its greatest width at a trapezoidal base. Also, the vertical support member may have a plurality of recesses with support columns located therebetween.

The anchoring device of the present invention may be fabricated with any available material, but is preferably made of molded plastic material capable of having a metal fastener driven through.

The present invention also relates to a decking system. It includes a plurality of decking boards, each decking board having a top, a bottom, two sides, and two ends, and at least one groove located along one of the sides. Preferably, there is a groove on both sides, except that end pieces may only have one groove. The groove adapted to receive the anchoring device described above, which is included in the system.

In preferred embodiments, the boards have an upper portion above the slots which is wider than a lower portion below the slots.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention should be more fully understood when the specification herein is taken in conjunction with the drawings appended hereto wherein:

FIG. 1 illustrates a top view of one preferred embodiment of the present invention anchoring device, FIG. 2 illustrates a front view, and FIG. 3 illustrates an end view thereof;

FIG. 4 illustrates a detailed end view of the present invention anchoring device shown in FIGS. 1, 2 and 3, with relative width illustrated;

FIGS. 5 and 6 show alternative embodiment top views of present invention anchoring devices;

FIG. 7 shows a cross-sectional, end view of the present invention device shown in FIGS. 1 through 3 but being attached to a joist and a first deck board and a second deck board where both deck boards are supported by that joist;

FIG. 8 shows a cross-sectional, end view of a preferred present invention decking system board; and

FIG. 9 shows an enlarged view of a portion of FIG. 7, including portions of the joist and first and second deck boards, and the present anchoring device anchored by a screw driven therethrough.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In FIG. 1, there is shown a top view of present invention anchoring device 1. Device 1 includes a top element 2 having a flat top surface 3 as shown, and a top view shape of a rectangle. It includes walls 5 and 7, which are parallel to one another in preferred embodiments, but need not be parallel to be within the scope of the present invention. In this case, they are perfectly symmetrical and have flat sidewalls 5 and 7. Perfect symmetry is preferred but not essential. Without exceeding the scope of the present invention, these top element shapes could be slightly modified, such as having non-linear segments, e.g., arcs or linear segments at angles.

Top element 2 also includes an imaginary center line 8 below which extends a vertical support member and a bottom element.

FIGS. 2 and 3 show front and end (right side) views, respectively of device 1 shown in FIG. 1. Thus, device 1 includes top element 2. a vertical support member 4 with walls 9 and 11, and recesses such as recess 17, creating support columns, such as column 19. Bottom element 6 has a substantially flat horizontal bottom surface 21 and tapered walls 13 and 15. Anchoring device 1 has a predetermined height so as to rest on a joist in such a way as to establish anchor top element 2 at a predetermined height from the joist for attachment of two adjacent boards thereto which have pre-cut slots corresponding thereto.

FIG. 4 shows a blown up end view of anchoring device 1 as shown in FIG. 3, with identical parts identically numbered in part, and with width designations, as illustrated. Specifically, in FIG. 4, top element 2 has a width W_(T), as measured from side to side at its maximum width. Vertical support member 4 has width W_(M), as measured from side to side at its maximum width. Likewise, bottom element 6 has a width W_(B), as measured from side to side at its maximum width. It is important to note that W_(T), the first predetermined width, being the width of top element 2, is greater than both W_(M), the predetermined width of vertical support member 4, as well as W_(B), the predetermined width, being a third predetermined width of bottom element 6. In other words, the width of the top element is greater than both the width of the vertical support member and the width of the bottom element. Moreover, the width of bottom element 6, W_(B), while it is less than width W_(T) of top element 2, it is also greater than the width of vertical support member 4, W_(B). These critical relationships allow for a maximum support of adjoining slotted boards while minimizing the space between the boards to typical or conventional deck spacing.

FIG. 5 and FIG. 6 show top views, respected with, of present invention anchoring device 31 and 41 to nearly illustrate that the top view of the top element need not be of parallel sides. Anchoring device 31 of FIG. 5 has parallel sides which are tapered at both ends while anchoring device 41 of FIG. 6 has subsequently not parallel, non-symmetrical sides. Parallel, symmetrical, mirror image sides are preferred in the present invention anchoring device but as now can be seen, variations may be made without exceeding the scope of the present invention.

FIG. 7 shows present invention anchoring device 51 in use. The cross-section presented in FIG. 7 is taken in a plane generally perpendicular to the long direction of horizontal beams (decking boards) 45 and 47 and the long direction of anchoring device 51 and generally parallel to the sides of joist beam 59. Anchoring device 51 is inserted into pre-cut slot 55 of horizontal beam 45, shown in its end view of cut wood 75. A staple, nail or screw is passed through anchoring device 51 into joist beam 59. Large staples are preferred and simplest for attachment. This anchor attaches device 51 to joist beam 59 and establishes the elevation of top element 2 so as to match with slot 55. As depicted in FIG. 7, the cross-section of anchoring device 51 may include a bottom portion having slightly curved sides to accommodate use in decking installations in which the decking boards have curved sides, such as those of the upper portion 61 and the lower portion 63 of the sides of decking board 45, as shown in FIG. 8.

Next beam 47 with its slot 57 in its end view cut wood 53 will be placed adjacent to anchoring device by being slid into position with the top element of anchoring device 1-51 fitting into slot 57 and the bottom of beam 47 resting on joint 59. By this method, anchoring device 51 attaches all three boards to one another as the top element aspects are typically tight-fitting. The bottom element also aids in placement and security by fitting under the edge of the beams as shown in the Figure. Thus, for example, decking boards may be attached without the need for nails or screws entering the beams themselves from the top.

FIG. 8 shows a detailed cross-sectional view of beam 45 from FIG. 7, the cross-section being taken in a plane generally perpendicular to the long direction of beam 45. This is a preferred component of the present invention decking system. As can be seen, the slot 55 represents a midpoint or approximate midpoint imaginary line 65 divides the beam into an upper or top portion 67, and a lower or bottom portion 69. As can be seen, the top portion 67 has a greater width W_(TB), than the bottom portion W_(BB). This provides for tightness of the anchoring device, increases stability and hides more of the anchoring device from a top view, enabling tight top portion beam spacing, yet enabling thicker anchoring devices for strength and stability.

FIG. 9 shows in enlarged view a portion of the cross-sectional view of FIG. 7, as indicated by circle IX. The enlarged portion in FIG. 9 depicts the attachment of anchoring device 51 by screw 52 driven therethrough and into beam 59. The respective sides of the top element portion of device 51 engage respective receiving slots 55, 57 of the decking boards.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. 

1. A decking system which comprises: I. a plurality of decking boards, a support board, an anchoring device, each decking board having a top portion, a bottom portion, two sides, and two ends, and at least one groove located along one of said sides, said at least one groove being adapted and dimensioned to receive the anchoring device, said decking boards being situated atop said support board; and II. the anchoring device comprising: (a) a substantially flat horizontal top element having a top view configuration which includes two substantially parallel sides and has a first predetermined width as measured side to side, said first predetermined width being measured at a maximum width between said sides of said top element, said top element having an imaginary center line and each of the sides of said top element being configured to be received in the at least one groove; (b) at least one substantially vertical support member attached to an underside of said top element along said imaginary center line of said top element and extending downwardly therefrom for a predetermined length, the at least one substantially vertical support member having two sides and a second predetermined width as measured side to side at a maximum width thereof; and (c) a substantially flat horizontal bottom element having a flat bottom view configuration which includes two sides and having a generally trapezoidal shape, and having a third predetermined width as measured side to side at a maximum width thereof; wherein said first predetermined width is greater than both said second predetermined width and third predetermined width, and wherein said third predetermined width is greater than said second predetermined width, and said anchoring device is adapted to maintain said top element in a predetermined position during use for joinder of two adjacent decking boards of the plurality of decking boards which each having been pre-cut with the at least one groove, and to position said bottom element upon said support board on which said two adjacent decking boards rest for attachment of said anchoring device to said support board for anchoring and support of said two adjacent decking boards; and, wherein said anchoring device is made of molded plastic material; and further wherein said horizontal top element is received in the at least one groove of each decking board of the two adjacent decking boards, said bottom element rests upon said support board, and said anchoring device is anchored by a metal fastener driven therethrough to said support board, whereby said anchoring device joins and supports said decking boards on said support board; and wherein the at least one vertical support member of said anchoring device has a plurality of recesses with support columns located therebetween, the support columns being disposed along one of the two sides of the at least one vertical support member, the plurality of recesses being disposed on each of the two sides of the at least one vertical support member.
 2. The decking system of claim 1 wherein the at least one groove divides the top portion and the bottom portion of each decking board, wherein the top portion has a greater width than said lower half.
 3. The decking system of claim 1 wherein said plurality of decking boards are made of materials selected from the group consisting of synthetic polymers, at least partially foamed synthetic polymers, wood, wood composite, and combinations thereof.
 4. A decking system, comprising: first and second deck boards, each of the first and second deck boards having a top portion, a bottom portion, at least two sides, at least two ends, and a groove located along at least one of the at least two sides, each of the first and second deck boards defining a central axis extending along a width thereof, the central axis being positioned at about a midpoint of a height of each deck board, the central axis dividing the top portion and the bottom portion of each of the first and second deck boards, the groove of each of the first and second deck boards being positioned along the central axis, the top portion of each of the first and second deck boards having a greater width than the bottom portion; a support board supporting the first and second deck boards; and an anchoring device, comprising: a top element having at least two sides and a substantially flat top portion, the top element having a first maximum width, the first maximum width being measured between the at least two sides of the top element, each of the at least two sides of the top element being dimensioned to be received within the groove of the first or second deck board; a support member extending transversely from the substantially flat top element and having at least two sides, the support member having a second maximum width, the second maximum width being measured between the at least two sides of the support member; a plurality of columns disposed along the at least two sides of the support member; a plurality of recesses disposed along each of the at least two sides of the support member, each of the plurality of recesses being located between at least two columns of the plurality of columns; a bottom element transversely connected to the support member and having at least two sides and a substantially flat bottom portion, the bottom element having a substantially trapezoidal shape and a third maximum width, the third maximum width being measured between the at least two sides of the bottom element; wherein the first maximum width is greater than both the second and third maximum widths, and the third maximum width is greater than the second maximum width; wherein the anchoring device is positioned between the first and second deck boards, each of the at least two sides of the top element being positioned inside the groove of the first or second deck board, and the bottom element resting on the support board.
 5. A decking system, comprising: first and second deck boards, each of the first and second deck boards having a top portion, a bottom portion, at least two sides, at least two ends, and a groove located along at least one of the at least two sides; a support board supporting the first and second deck boards; and an anchoring device, comprising: a top element having at least two sides and a substantially flat top portion, the top element having a first maximum width, the first maximum width being measured between the at least two sides of the top element, each of the at least two sides of the top element being dimensioned to be received within the groove of the first or second deck board; a support member extending transversely from the substantially flat top element and having at least two sides, the support member having a second maximum width, the second maximum width being measured between the at least two sides of the support member; a plurality of columns disposed along the at least two sides of the support member; a plurality of recesses disposed along each of the at least two sides of the support member, each of the plurality of recesses being located between at least two columns of the plurality of columns; a bottom element transversely connected to the support member and having at least two sides and a substantially flat bottom portion, the bottom element having a substantially trapezoidal shape and a third maximum width, the third maximum width being measured between the at least two sides of the bottom element; wherein the first maximum width is greater than both the second and third maximum widths, and the third maximum width is greater than the second maximum width; wherein the anchoring device is positioned between the first and second deck boards, each of the at least two sides of the top element being positioned inside the groove of the first or second deck board, and the bottom element resting on the support board.
 6. The decking system according to claim 5, wherein each of the plurality of columns extends longitudinally between the top element and the bottom element of the anchoring device.
 7. The decking system according to claim 5, wherein each of the first and second deck boards defines a central axis extending along a width thereof, the central axis being positioned at about a midpoint of a height of each deck board, the central axis dividing the top portion and the bottom portion of each of the first and second deck boards, the top portion of each of the first and second deck boards having a greater width than the bottom portion.
 8. The decking system according to claim 7, wherein the groove of each of the first and second deck boards is disposed along the central axis. 